Method of blowing blast into shaft furnaces



Nov. 3, 1931. 1,830,683

METHOD OF BLOWING BLAST INTO SHAFT FURNACES A. WAGNER ET AL,

Filed July 11, 1927 Patented Nov. 3, 1931 UNITED STATES PATENT OFFICE ALFONS WAGNER, F DUISIBURG, AND EDUARD POHI; 0F RHONDORF-ON-THE-RHINE,

GERMANY, ASSIGNORS TO GUTEHOFFNUNGSHTTTTE OBERI-IAUSEN AKTIENG-ESELL- SCHAFT, OF OBERHAUSEN, GERMANY, A CORPORATION OF GERMANY METHOD OF BLOWING BLAST INTO SHAFT FURNACES Application filed July 11, 1927, Serial No.

,In shaft furnaces, hitherto, the blast is blown into the shaft through tuyeres in such a way that it exerts a vigorous suction (that isaspira ting or injector) effect on the furnace gases at about the whole length of its jet that is directed at right angles to the vertical axis of the furnace shaft, whereby in the latter an oxidizing zone is created which extends from the mouth of the tuyere toward the middle of the furnace shaft in about elliptical formation and acts detrimentally upon the working of the shaft furnace while it requires an excessive consumption of coke.

The present invention relates to an improved method, and an improved construction of tuyeres for putting the same into practice, of decreasing the noxious effect of said oxidizing zone by reducing the kinetic energy of the blast and changing it partly to pressure whereby the incoming blast is diverged and the oxidizing zone is dis laced from its noxious position mentione to a practically neutral position extending in up and downward directions from the mouth of the tuyere along the inner walls of the furnace shaft. To this end, according to the invention, the inner bore of the tuyere is tapered from the mouth of the tuyere toward the rear inlet end thereof, which taper extends either at a short distance from the mouth only, or over, part of the length of the tuyere, or over its whole length.

In the accompanying drawings:

Figure 1 shows in longitudinal section a tuyere of conventional type showing schematically the conventional shape and chemical composition of the blast stream emitted by said tuyere;

Figure 1A is a sectional view, on an enlarged scale, taken along the plane indicated by the arrows 1A-1A of Figure 1, indicating the bulbous nature of the blast emitted 45 by the tuyere shown in Figure 1;

Figure 1B is a sectional view, on an enlarged scale, taken along the plane indicated by the arrows 1B1B ofEigure 1;

Figure 2 shows in longitudinal section a v tuyere embodying the principles of the pres- 204,929, and in Germany October 15, 1926.

ent invention, indicating schematically the blast stream emitted by said tuyre;

Figure 2A is a sectional view taken along the plane indicated by the arrows 2A--2A of Figure 2; and

Figures 3, 4 and 5 illustrate other forms blast stream emitted by said tuyre; present invention.

The numeral 1 indicates a tuyere of conventional type mounted in the-wall 2 of a shaft furnace and projecting beyond the lining of said wall. The numeral 3 indicates schematically the typical blast stream emit- 'ted'by said tuyere 1. It will be noted that the blast 3 comprises a central core 3a of air, indicated by the characters 0 -0 indicating oxygen.

Inasmuch as said tuyere has a continuously converging Wall, the blast stream 3 enters the furnace with suction effect (that is, the well known aspirating or injector effect characterized particularly by theconstricted throat of the blast stream 36), whereby the surrounding furnace gases, consisting largee ly of carbon monoxide C0, are strongly induced to flow into and mingle with the blast stream. The movement of furnace gases is indicated by the curved arrows. The deleterious effects of this action are two-fold. First, there is a mechanical action by the induced gas flow upon the adjacent wallof the furnace which is destructive; and, second, carbon monoxide gas combines with the air or oxygen in the blast 3, forming a layer 30 of carbon dioxide CO which is, in 85 a blast furnace,an oxidizing gas. The numerals 3d and 3e indicate particles of coke and iron, respectively, coming in contact with the oxidizing layer 30, resulting in the uneconomical consumption of said particles of coke and the oxidation of said particles of iron. Due to the relatively high kinetic energy of the gas produced by the conventional type of tuyere shownin Figure 1, said blast is elongated a relatively great distance toward the axis ,of the furnace, establishing anextensive oxidizing zone having a decidedly deleterious effect -upon the coke consumption and in iron oxidation.

' In the construction shownin Fig. 2, the 10C inner bore of the tuyere 4 is tapered at 5 from in up and downward directions from the mouth of the tuyere.

In the preferred Fig. 4, the taper 11 of the inner bore of the tuyere 10 extends from the mduth toward the rear end of the latter over part of the length thereof, the oxidizing zone 12 being thereby also displaced in u and downward directions from the mouth 0 the tuyere along the inner walls of the furnace shaft 13.

In the construction shown in Fig. 5,. a separate blast nozzle 14 extends through the rear inlet end of the tuyere 15, of which the inner bore is tapered at 16 over its whole length, to about the middle thereof and has perforations 17 distributed over its circumference and located at a distance from its a mouth; the improved action mentioned of displacing the oxidizing zone in front of the forations and 7 tion. 5 of the tuyere 4 increases pro tuyere mouth being thereby further increased,

as the incominglolast is throttled by said perrther b the taper 16. Preferably, the inner ore of the improved construction shown in than is the core of'air O in the conventional structure shown in Figure 1, the oxidizing envelope CO is more uickly reconverted to CO in the disclosure 0 Figure 2 than is the case in the disclosure of Figure 1. The method of distributing the air as disclosed in Figure 2 therefore materiall reduces the 0x1- dizing zone from that pro need in the mouth as illustrated in Figure 1.

As indicated above, the method as produced by the structure shown in Figures 3, 4 and 5 will be clear from that discussed in connection with Fi re 2.

What we claim, 1s: a

1. In the operation ofblast furnaces, the

improvement which consists in conductin the air blast in a converging funnel-shape formation and thereafter in a flaring funnelshaped formation into the furnace gas without injector effect and thereby diminishing the premature burning of the furnace gases and fuel as well as diminishing the dimension of the oxidizing zone in its longitudinal axis. in the tuyere plane of the furnace.

2. The improvement described in claim 1, in which the air blast is introduced into the furnace with its kinetic energy partially converted into ener or pressure.

In testimony w ereof we have hereunto set our hands.

ALFONS WAGNER. EDUARD POHL.

tuyere directly at the mouth thereof may be rounded in funnel-shaped fashion as indi-' cated at 18 in Fig. 5, whereby the diverging action upon the incoming blast is further creased.

The underlying rinciples of the present invention willbe c ear from a discussion of the method as carried out in connection with the tuyere illustrated in Figure 2. Referblast stream issuing from the tapered porgressively in diameter from the tuyere mouth, whereby the injector action upon the carbon monoxide gas within the furnace is minimized.- Moreover, due to the fact that the blast is flared in all directions transversely of the axis of ring to said figure, it will be noted that the the tuyere, the distance to which said blast y is pro ected into the furnace is minimized.

According to the disclosure in Figure 2, the injector action on the surroundlng furnace gases consisting large] of carbon monoxide 0 is substantially eliminated. Due, however, to the presence of particles 3d of carbon in the form of coke, the inner core of oxygen O is converted to an envelope of G0,, which, as stated above is, in a blast furnace an oxidizing gas; and further into CO. liowever, due to the fact that thecore of air 0, is much shorter in the structure disclosed in Figure 2.

i Mi

CERTIFICATE or commotion.

Patent No. 1,830,683. Granted November 3, 1931, to

'ALFONS WAGNER and EDUARD POHL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, line 57, strike out the words and semi-col0n "blast stream emitted by said tuyere;" and insert instead of tuye e embodying the principles of the; page 2, line 93, claim 2, for "or" read of; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 9th day of February, A. D. 1932.

M. J. Moore, .(Seal) Acting Commissioner of Patents. 

